Sylvania



- Reiaued Aug. 2, 1932 j UNITED srATas PATENT" orrlca s. TAYLOR, or rmw'xnnsme'rou, AND JUNIUS n. nnwanns, or oanrom', rm-

assrenons 1'0 ammmum comramr or AMEBICA, or 'rrr'rsauaen, PENNSYLVANIA, a coarona'rrox or rnmrsvnvama momma aLLoY are nmnn Original in. 1 mm, dated November 8, 1931, Serial No. 545,490, filed June 19, 1931.

Application for reissue med December 81, 1931. Serial No. 582,511

The invention relates to aluminum base alloys of relatively low electrical conductimty. There are certain uses for aluminum base alloys of low electrical conductivity among 5 them being two well known examples, viz.,

for the rotors or cages of motors, and for electric current meter discs. Thus, in motors designed to have a high starting torque, the rotors are commonly cast or built up of aluminum, and for such ap lications it is highly desirable that thecon uctivity of the metal be as low as possible.

It is an object of our invention to provide an .alloy of low electrical conductivity suit- 16 able to these andother uses. A further object of the invention is to provide an alloy of uniform physical and electrical characteristics which can be economically produced.

Throughout the description of our inven- 20 tion, all values of conductivity are expressed by percentage figures, denotin in, every case the ratio of the conductivity 0 the aluminum alloy to that of the international annealed copper standard at 20 centi grade, the re-' sistlvity of which is'1.7241 microhms per cm.

We havefound that certain metals, when added'to aluminum in small quantities, have the effect of depressing the conductivity of the aluminum. These metals are titanium,

30 vanadium chromium, manganese, and zirconium. e have discovered, further, that the best and most consistent results are obtained when two. or more of these added metals are used together. Manganese, when used alone, 1 reduces a "very substantial reduction in con uctivity, but'its effect-cannot be predicted .with certaint and we have foundthat it is desirable tov a d a small amount of zircomum, vanadium or chromium to the alloy to insure uniformity of results and further depress 1 the} conductivity. Where manganese an zirconium are the added elements, small amounts of titanium and/or vanadium .an'd/or chromium may also be added." An

aluminum-manganese-vanadium alloy or an- -aluminum-manganese-chromium alloy gives .very satisfactory results as far as lowering the conductivity is concerned, but zirconium,

when added'to an aluminum-man ese al-.

. 59 loy, with or without the presence 0 the other elements above mentioned, namely, vanadium, titanium or chromium, is productive of certain additlonal advantages which make the caluminum-manganese-zirconium alloys much to be preferred. Alloys of this nature and containing zirconium may be conveniently rolled or otherwise worked, and appear to cast somewhat better than the other alloys herein mentioned. Thus, the aluminum? manganese-zirconium alloys are better suited-to the manufacture of rolled parts, such as may be fabricatedfrom sheet or bars or rgds, 'as well as to the manufacture of castings. In addition to the elements so far named, zinc, copper, magnesium, and similar metals or'combinations of these metals may also he added in amounts of, say 2 to 10 per cent to further control the casting properties of the alloys.

The manganese content .of the alloy may range from about 0.5 to 8 per cent but we prefer to use amounts up to about 4 per cent where malleability pf the alloy is a factor in its selection. Zirconium is preferably added to the alloys in amounts of about 0.05 to 3 per cent. The total proportion of zirconium,

titanium, vanadium and/0r chromium may efl'ec't of the various added metals,

formly low conductivity. We consider man-. I

ganese and zirconium to 'be the essential ingredients for the best results. Pure aluminum has a-conductivity of about 64 per cent. 0.1 percent of-titanium.(atomic number, 22), when added alone to pure aluminum, de-

. creases the conductivity about 7.6 percerit.v

0.1 per centof vanadium (atomic number, 23) decreases the conductivity of aluminum about 9.6 per cent. 0.1 r cent of chromium (atomic number, 24) ecreases the conductivity of aluminum about 6.6 per cent. A like amount of manganese (atomic number, 5 25) produces a decrease of around 6.0 per cent. A like amount of zirconium (atomic number, 40) produces a decrease of around 5.0 per cent.

While in describing our invention we have,

in the interests of clarity, employed specific language, we have no intention, in the use of such language, of excluding any equivaf lfeuts or minor variations of the invention set orth.

We claim:

1. An aluminumalloy of low electrical conductivity containing "manganese from about 0.5 to about 8 per cent and containing from about 0.05 to 3 per cent of zirconium.

2. An aluminum alloy of low electrical conductivity containing from about 0.5 to about 8 per cent of manganese and about'0.5 per cent of zirconium.

3; An aluminum alloy of low electrical conductivity containing from about 0.5 to 8 per cent of manganese and from about 0.05 to 3 per cent altogether of zirconium and a metal from the group composed of titanium, vanadium and chromium.

3 4. An aluminum alloy of low electrical conductivity containing from about 0.5 to about 8 per cent of manganese, and one of the elements zirconium, vanadium and chromium in the amount of not less than about 0.05 per 7 cent and not more than about 3 per cent, the

balance being substantially a1uminum.

5. An aluminum alloy of low electrical conductivity containing manganese from about 0.5 to 4 per cent and containing at least 40 0.05 per cent of zirconium and of a metal from the group composed of titanium, vanadium and chromium, the total amount of said metal and the zirconium not exceeding about 3 per cent.

v 6. An aluminum alloy of low electrical conductivity containing from about 0.5 to about 8 per, cent of manganese, and one or vmore of the elements zirconium,'vanadium and chromium in the total amount of not less than about 0.05 per cent and not more than about 3 per cent, the balance being substantially aluminum.

1 CYRIL S. TAYLOR.

JUNIUS D. EDWARDS. 

